MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          check(free(x)) -> free(check(x))
          check(new(x)) -> new(check(x))
          check(old(x)) -> old(x)
          check(old(x)) -> old(check(x))
          new(free(x)) -> free(new(x))
          new(serve()) -> free(serve())
          old(free(x)) -> free(old(x))
          old(serve()) -> free(serve())
          top(free(x)) -> top(check(new(x)))
      - Signature:
          {check/1,new/1,old/1,top/1} / {free/1,serve/0}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {check,new,old,top} and constructors {free,serve}
  + Applied Processor:
      NaturalPI {shape = Mixed 3, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE